Browser Takeover Bridge

Public beta — the core browser-control path is tested and usable. Store distribution and third-party browser compatibility certification are still in progress.

Product website · Download v0.6.0

Install In Codex

Add this repository as a Codex Marketplace source, then install the plugin:

codex plugin marketplace add fangsylar-pixel/browser-takeover-bridge
codex plugin add browser-takeover@browser-takeover-marketplace

Restart Codex and open a new thread after installation. The companion Chrome or Edge extension still needs to be loaded once from browser-takeover/extension or the release ZIP.

Install In MARVIS

MARVIS can load the Browser Takeover skill files, but some versions do not automatically register the bundled browser-takeover/.mcp.json. If the skill appears installed but no browser_takeover_* tools are available, add the MCP server manually in MARVIS:

{
  "mcpServers": {
    "browser-takeover": {
      "command": "python",
      "args": [
        "C:\\absolute\\path\\to\\browser-takeover\\scripts\\browser_takeover_mcp.py"
      ]
    }
  }
}

Use an absolute path because MARVIS may start MCP servers from a different working directory. Restart MARVIS after saving the MCP configuration, then open a new conversation and confirm that browser_takeover_extension_bridge_status is available.

The companion extension is still required:

1. Open chrome://extensions or edge://extensions.
2. Enable developer mode.
3. Choose Load unpacked.
4. Select the installed browser-takeover/extension directory.

MARVIS Troubleshooting

• Tools are missing: the skill was copied, but the MCP server was not registered. Add the configuration above and restart MARVIS.
• Port 17321 is listening, but MARVIS shows no tools: a detached browser_takeover_mcp.py process is running outside MARVIS. Stop that process before restarting the registered MCP server to avoid a port conflict.
• clients: [] or tabCount: 0: no extension client is connected. Check that the unpacked extension is loaded in the same Chrome or Edge profile that owns the target tabs.
• Bridge status is healthy but tabs are unavailable: open a normal web page in that browser profile and check the extension popup for paused automation, trusted-site restrictions, or connection errors.

A healthy installation has all three layers connected: MARVIS lists the MCP tools, the local bridge answers on 127.0.0.1:17321, and bridge diagnostics report at least one fresh extension client.

Browser Takeover is a local-first browser control layer that lets AI agents work with Chrome and Edge tabs that are already open and already authenticated.

Unlike browser automation that forces users into a fresh profile, Browser Takeover works with the session they already trust. It adds visible safety controls, trusted-site restrictions, diagnostic health reporting, and an open local protocol for Codex and other MCP-compatible agents.

Most browser automation tools need a new browser profile or a browser that was started with a remote debugging port. This project adds a companion extension and localhost bridge so an agent can discover and control the user's normal Chrome or Edge tabs without asking the user to log in again.

What It Can Do

• List already-open Chrome or Edge tabs from the user's normal browser profile.
• Read visible page text and DOM structure.
• Type prompts, click buttons, navigate tabs, and capture screenshots.
• Fetch image resources that require the browser's logged-in session.
• Fall back to Chrome DevTools Protocol for browsers launched with --remote-debugging-port.
• Claim tabs using renewable readonly or interactive leases.
• Use a structured action protocol for reliable click, fill, read, press, select, and snapshot operations.
• Authenticate extension traffic to the localhost bridge with a per-extension token.
• Display live connection health and errors in the extension popup.
• Stream tab lifecycle events and capture multiple open tabs in one readonly batch.
• Persist webpage monitors, compare readonly snapshots, and detect text or numeric conditions.
• Verify write actions using observable URL, text, element, or value evidence.
• Pause all automation instantly from the extension popup.
• Restrict control to an explicit trusted-site list.
• Copy privacy-safe diagnostics for support and team troubleshooting.
• Wait for SPA navigation to satisfy URL, selector, and text evidence before reporting success.
• Discover custom clickable controls and return reusable selectors in structured snapshots.
• Traverse DOM pagination with deduplication, partial-result recovery, and explicit stop reasons.

Verified locally with:

• ChatGPT: send prompts and download generated images.
• Feishu/Lark Docs: read document text and download embedded images.
• Toutiao: read authenticated pages and capture screenshots.

Webpage Monitoring In MARVIS

Browser Takeover can now monitor content in an already-open Chrome or Edge tab. The MCP server stores monitor definitions and snapshot history locally; MARVIS Automatic Tasks supplies the schedule. Monitoring reuses the extension's readonly claim system and does not add browser permissions.

Quick start

After installing the plugin and confirming that browser_takeover_extension_bridge_status reports a connected client:

1. Open the page you want to monitor in the connected browser profile.
2. Ask MARVIS to create a monitor. Prefer a stable CSS or semantic target instead of the entire page, because clocks, advertisements, and rotating recommendations can create noisy changes.
3. Run the monitor once to create its baseline.
4. Add a MARVIS Automatic Task that checks it at the desired interval.
5. Notify only when newlyTriggered is true, and include the returned diff and source URL.

Example prompts:

监控当前商品页面的 .price 元素，价格低于 500 元时提醒我。先检查一次建立基线。

监控这个报名页面的正文；出现“立即报名”时提醒我，并附上变化内容和页面链接。

每天上午 9 点检查这个游戏公告页面，有变化时告诉我新增或删除了哪些内容。

Trigger rules

Rule	Purpose	Example
changed	Any content change after the first baseline	Announcement or policy updates
contains	Text appears	立即报名, 有货
not_contains	Text disappears	Maintenance banner removed
equals	Exact text match	Status becomes 已开放
regex	Pattern match	Version numbers or structured status text
number_above	Extracted number exceeds a threshold	Score, capacity, or queue length
number_below	Extracted number falls below a threshold	Product price

For prices or other mixed text, provide numberPattern with a capture group, for example ¥([\\d,]+(?:\\.\\d+)?).

Monitor tools

• browser_takeover_monitor_create: create a persistent monitor.
• browser_takeover_monitor_check: capture content, compare it with the last snapshot, evaluate the rule, and save history.
• browser_takeover_monitor_list: list active or paused monitors without returning stored page content.
• browser_takeover_monitor_history: inspect recent checks; content is excluded unless includeContent is explicitly enabled.
• browser_takeover_monitor_update: pause, resume, rename, or replace a trigger rule.
• browser_takeover_monitor_delete: permanently remove a monitor and its local history.

On Windows, monitor data defaults to %LOCALAPPDATA%\\BrowserTakeover\\monitors.json. On other systems it defaults to ~/.browser-takeover/monitors.json. Set BROWSER_TAKEOVER_MONITOR_FILE to choose another location. History from authenticated pages may be sensitive, so do not sync or share this file unintentionally.

The monitor module deliberately does not buy, submit, publish, or bypass CAPTCHA/login controls. Those remain separate interactive actions and require explicit authorization.

Project Layout

browser-takeover/
  .codex-plugin/plugin.json
  .mcp.json
  extension/
    manifest.json
    background.js
  scripts/
    browser_takeover_mcp.py
    webpage_monitor.py
  skills/
    browser-takeover/SKILL.md
  README.md
website/
  src/
  public/
  package.json

Download And Verify

GitHub releases contain:

• browser-takeover-extension-<version>.zip for loading the companion extension.
• browser-takeover-plugin-<version>.zip for Codex or MCP-compatible local installation.
• SHA256SUMS.txt for integrity verification.

Maintainers can reproduce these files locally with:

python browser-takeover/scripts/verify_release.py

Product Website

The bilingual product website lives in website/. It automatically selects Chinese or English from the browser locale and includes a manual language switch.

Public website: https://fangsylar-pixel.github.io/browser-takeover-bridge/

cd website
npm install
npm run dev

How It Works

1. The MCP server starts a local bridge on 127.0.0.1:17321.
2. The browser extension polls that bridge from the user's normal browser profile.
3. The extension reports open tabs and executes requested commands in those tabs.
4. Results are returned to the local MCP server.

The bridge is local-only. It does not expose a public network service.

Install The Extension

1. Open edge://extensions or chrome://extensions.
2. Enable developer mode.
3. Click "Load unpacked".
4. Select:

browser-takeover/extension

MCP Server

The plugin MCP entrypoint is:

browser-takeover/scripts/browser_takeover_mcp.py

Useful tools include:

• browser_takeover_extension_bridge_status
• browser_takeover_extension_list_tabs
• browser_takeover_extension_reload
• browser_takeover_extension_evaluate
• browser_takeover_extension_navigate
• browser_takeover_extension_screenshot
• browser_takeover_claim_tab
• browser_takeover_renew_claim
• browser_takeover_release_tab
• browser_takeover_extension_action
• browser_takeover_monitor_create
• browser_takeover_monitor_check
• browser_takeover_monitor_list
• browser_takeover_monitor_history
• browser_takeover_monitor_update
• browser_takeover_monitor_delete

Security Model

• The extension must be installed by the user.
• The bridge listens only on 127.0.0.1.
• Users can pause automation globally at any time.
• Users can restrict commands to trusted hostnames from the popup.
• Extension traffic is authenticated after registration and CORS is restricted to extension origins.
• The agent can only access tabs in the browser profile where the extension is installed.
• The project does not bypass authentication, permissions, CAPTCHAs, paywalls, or browser security boundaries.
• Treat every connected page as sensitive. Avoid logging private document contents, signed URLs, or account data.

Read the full privacy policy, security policy, and terms of use before deploying the bridge in a team environment. For troubleshooting, see the support guide.

CDP Boundary

An ordinary Chrome or Edge window cannot be attached through CDP after launch unless it was started with a flag such as:

msedge.exe --remote-debugging-port=9222
chrome.exe --remote-debugging-port=9222

The extension bridge exists to cover the practical case where the user already has the page open in their normal logged-in browser.

Why Teams Choose Browser Takeover

• Local-first: the control bridge is bound to localhost.
• Browser choice: supports both Chrome and Edge.
• Existing sessions: works with tabs where the user is already signed in.
• Operational safety: pause switch, trusted-site mode, claims, leases, and evidence checks.
• Built for hard pages: Shadow DOM, iframes, uploads, downloads, native input, and full-page capture.
• Open integration: a documented MCP surface instead of a single-vendor workflow.

Support

Browser Takeover Bridge is open source and built for people experimenting with Codex, browser agents, and authenticated web workflows.

If it helps you, optional support is welcome:

Support on Afdian

Bug reports and contributions are welcome. See CONTRIBUTING.md.

License

MIT